International Chronostratigraphic Timescale

The interval definitions in this timescale are derived from the following sources:

  • K. M. Cohen, S.C. Finney, P.L. Gibbard and J.-X. Fan. 2023. The ICS International Chronostratigraphic Chart v2023/09. view
  • F. M. Gradstein, J. G. Ogg, and A. G. Smith. 2004. A Geologic Time Scale 2004 1-589 view
  • W. B. Harland, R. L. Armstrong, A. V. Cox, L. E. Craig, A. G. Smith and D. G. Smith. 1990. A Geologic Time Scale 1989. view
  • F. M. Gradstein, J. G. Ogg, M. D. Schmitz and G. M. Ogg. 2020. Geologic Time Scale 2020 view
  • J. Palfy, P. L. Smith, and J. K. Mortensen. 2000. A U-Pb and 40Ar/39Ar time scale for the Jurassic. Canadian Journal of Earth Sciences 37(6):923-944 view

There are 59 timescales which overlap this one. show

Interval boundaries marked with * have been interpolated based on the differences between the ages for international timescale boundaries quoted in the source and the currently accepted ages for those boundaries.

Interval names marked with † are no longer in current use.

This timescale is used in the definition of 128057 collections

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International Chronostratigraphic TimescaleDevonian of Eastern North AmericaCambrian of North AmericaCambrian of West AvaloniaCambrian of KazakhstanObsolete Precambrian AgesSilurian of EnglandCarboniferous of North AmericaDevonian of FranceAmmonite Chrons of Northwest Europe
PhanerozoicMesozoicJurassicMiddle JurassicBajocianParkinsoni/Garantiana/Subfurcatum/Sauzei/Laeviuscula/Discites168.2
Humphresianum168.4
AalenianConcavum/Murchisonae/Opalinum170.9
Early JurassicToarcianLevesquei/Variabilis/BifronsThouarsense174.7
180.1
Serpentinum/Falciferum/Tenuicostatum182
PliensbachianSpinatum/Margaritatus/Davoei/Ibex/Jamesoni184.2
SinemurianRaricostatum/Oxynotum/Obtusum/Turneri/Semicostatum/Bucklandi192.9
HettangianAngulata/Liasicus/Planorbis199.5
TriassicLate TriassicRhaetian201.4
Norian208.5
Carnian227
Middle TriassicLadinian237
Anisian242
Early TriassicOlenekian247.2
Induan251.2
PaleozoicPermianLopingianChanghsingian251.902
Wuchiapingian254.14
GuadalupianCapitanian259.51
Wordian264.28
Roadian266.9
CisuralianKungurian273.01
Artinskian283.5
Sakmarian290.1
AsselianBursumian †293.52
CarboniferousPennsylvanianGzhelianVirgilian298.9
KasimovianMissourian303.7
Desmoinesian305.9 *
Moscovian307
Atokan312.7 *
Bashkirian315.2
Morrowan318.4 *
MississippianSerpukhovianChesterian323.2
Visean330.9
Meramecian335.8 *
Osagean343.1 *
Tournaisian346.7
Kinderhookian351.9 *
DevonianLate DevonianFamennianConewangan/Conneautan/CanadawayFamennian358.9
FrasnianWest Fallsian/SonyeanFrasnian372.2
Middle DevonianGivetianGeneseean/Taghanican/TioughnioganCazenovianGivetian382.7
EifelianSouthwoodianCouvinien387.7
Early DevonianEmsianSawkillian/Deer ParkianHelderbergian393.3
Pragian407.6
Coblencien408.2 *
LochkovianGedinnine410.8
SilurianPridoliRed Downtonian/Temeside Shales/Downton CastleWhitcliffe/Leintwardine419.2
Bringewood/Elton421.3
LudlowLudfordianCoalbrookdaleWenlock (England)/Tickwood423
Gorstian425.6
Buildwas426.4 *
WenlockHomerian427.4
WychWoolhope428.4 *
Sheinwoodian430.5
LlandoveryTelychian433.4
436.3 *
Aeronian438.5
Cowleigh Park439.3 *
Rhuddanian440.8
OrdovicianLate OrdovicianHirnantian443.8
Katian445.2
Sandbian453
Middle OrdovicianDarriwilian458.4
Dapingian467.3
Early OrdovicianFloian470
TremadocianUngurian477.7
CambrianFurongianStage 10Franconian †/Dresbachian/MillardanBatyrbaian485.4
Sunwaptan487.5
Jiangshanian489.5
Aksaian490.7 *
Sakian492.2 *
Steptoean493 *
Paibian494
MiaolingianGuzhangianMarjumianAlbertian †Ayusokkanian497
Arcadian498.4
499.5
DrumianZhanaarykian500.5
Tuesaian503
WuliuanTopazan504.5
505.3
Delamaran506.5
Series 2Stage 4Waucoban †Branchian509
Toyonian510 *
Dyeran511 *
Botomian512.5 *
Stage 3514
Montezuman514.8 *
Atdabanian515.6 *
Placentian517.1
Begadean519.9 *
TerreneuvianStage 2Tommotian521
525.5
Fortunian529
ProterozoicNeoproterozoicEdiacaranVendian †Poundian †538.8
Wonokan †571.7 *
635